Power supply systems are implemented for a variety of electronic applications to convert one power voltage to another, such as from an AC power voltage to a DC power voltage or from a DC power voltage to another DC power voltage. At initiation of a power supply, activation of a switch to conduct a current, such as to charge an output capacitor, can result in a high inrush current. The high inrush current can exceed safe operating capacity of electronic devices in the power supply circuit, such as transistors associated with operating the power supply circuit. To control inrush current, circuits can be designed to provide a soft-start of the power supply circuit, such as to slowly increase the voltage at the output. Therefore, inrush current can be controlled to mitigate damage to the electronic devices of the power supply circuit.